1. Technical Field
Aspects of this document relate generally to telecommunication systems and techniques for transmitting data across a telecommunication channel.
2. Background Art
In digital communication receivers employing M-ary PSK or M-ary QAM, carrier frequency estimation is commonly accomplished using Fast Fourier Transform (FFT) together with modulation removal. As the symbol rate becomes low, that is, less than 32 kilosymbols/second, the frequency offset becomes larger relative to the symbol rate. Hence the acquisition range of the receiver becomes larger than the symbol rate as well. When the acquisition range of the receiver is 40 times the symbol rate, for example, frequency offset estimation known in the prior art will take 160 sequential FFT operations together with modulation removal for QPSK.
To reduce the length and complexity of the detailed description and to establish a current state of the art, Applicant hereby incorporates by reference in their entirety each reference listed in the numbered paragraphs below:
U.S. Pat. No. 4,904,930—Method of Carrier Frequency Estimation, David C. Nicholas, Feb. 27, 1990.
U.S. Pat. No. 4,912,422—Demodulation System for PSK Signals with Low Carrier to Noise Ratio and Large Frequency Offset, Kobayahi et al., Mar. 27, 1990.
U.S. Pat. No. 5,272,446—Digitally Implemented Fast Frequency Estimator/Demodulator for Low Bit Rte Maritime and Mobile Data Communications Without the Use of an Acquisition Preamble, Chalmers et al., Dec. 21, 1993.
U.S. Pat. No. 5,233,632—Communication system receiver apparatus and method for fast carrier acquisition, Baum et al., Aug. 3, 1993.
U.S. Pat. No. 7,151,807—Fast acquisition of timing an carrier frequency from received signal, Ernest C. Chen, Dec. 19, 2006.
U.S. Pat. No. 6,771,699—Method of rapid carrier-frequency offset acquisition using a periodic training sequence, Karaoquz, et al., Aug. 3, 2004.
Heinrich Meyr, Marc Moeneclaey, and Stefan A. Fechtel. Digital Communication Receivers: Synchronization, Channel Estimation, and Signal Processing. John Wiley & Sons, Inc. 1998. pages 457-462.
Bernard Sklar. Digital Communications: Fundamentals and Applications. Second Edition. Prentice Hall PTR. 2001. Pages 63-75 (Sampling Theorem) and Pages 598-643 (Synchronization).
Floyd M. Gardner. Phaselock Techniques. John Wiley & Sons, Inc. 1979.
Alain Blanchard. Phase-Locked Loops: Application to Coherent Receiver Design. John Wiley & Sons, Inc. 1976.
Roland E. Best. Phase-Locked Loops: Design, Simulation, and Applications. Fifth Edition. The McGraw-Hill Companies, Inc. 2003.
Ferdinand Classen and Heinrich Meyr. Two Frequency Estimation Schemes Operating Independently of Timing Information. IEEE 1993. Pages 1996-2000.